Storm surge flooding, a MAJOR problem for New York!
14 months ago New York City was struck by a weak category 1 hurricane.
You may remember all the press about Hurricane Irene as it moved up the Eastern Seaboard of the United States in late August of last year before arriving in New York City during the early morning hours on August 28th.
The storm came with a lot of fan fair and evacuations were ordered for much of the city. After all was said and done, the storm knocked out power to 350,000 homes and damage was estimated at around $300 million in New York.
Trees and powerlines were knocked down and heavy rains caused some urban flooding including the metro subway system.
Overall, however, the impacts of Irene generally were pretty weak in New York and paled in comparison to the expectations of many who were bracing for the storm.
Now we have Sandy.
Sandy is also a category 1 hurricane. However, that is where the comparisons end between these two storms.
Irene was a compact storm compared to Sandy, and Irene was also a fast mover as it swept through the Northeast in a matter of hours.
It was also a storm that was on the decline by the time that it reached the Mid Atlantic. (It was downgraded to a tropical storm as it made it's way on shore.)
Sandy, however, is slowly gaining strength and this storm is absolutely mammoth in size.
Recent bouy data has revealed that tropical storm force winds now extend nearly 500 miles from the center of circulation!
This storm has been gradually increasing in size over the last couple of days since it began to interact with stronger winds aloft.
Now, we are watching Hurricane Sandy phase with a powerful upper level storm system that is moving in from the west. An event so rare, that it hasn't been observed in more than two decades! (Since "The Perfect Storm" in 1991)
This is expected to further broaden and strengthen the already enormous wind field as the storm slowly churns to the north before making a sharp turn towards the coast sometime early tomorrow.
The National Hurricane Center is now forecasting Sandy to make landfall across the Southern New Jersey Coast late tomorrow.
With a typical tropical system, a track such as this would bring the worst of the weather just north of landfall, across the Central Jersey Coast.
However, this system is NOT typical! The one thing we know for sure though is that the affects of this storm will be felt over a very broad area.
In fact, the National Weather Service has issued High Wind Warnings for much of the Northeast and down into the Appalachians where Blizzard Warnings are also in effect.
This storm poses many hazards including the possibility of damaging winds, flooding rains, heavy snow and coastal flooding.
Of all of these threats, though, coastal flooding might be the greatest, especially for New York City and surrounding areas!
As with other tropical systems, a storm surge is created by the combination of lowered air pressure, the storms forward momentum and it's wind field.
This image from the National Hurricane Center shows the extent of Sandy's wind field as tropical storm force winds extend from near Bermuda all the way to the North Carolina Coast!
Already, we are seeing swells of 20 to 30 feet building off the Carolina Coast. These swells will only increase in size as the storm gets stronger and the wind field continues to increase.
Now, take a look at these projected winds from across the northeast tomorrow evening.
Notice the huge swath of 50, 60 and even 70 mph winds. They cover an area from Portland Maine through Washington DC. Gusts are expected to exceed 80 mph in some locations!
Storm surge flooding will be a big problem for areas to the north of where Sandy makes landfall. In particular, I think New York City is at major risk!
Unlike Irene, who came onshore near New York at a very shallow angle, Sandy looks to strike the coast head on!
The combination of the storms forward momentum in from the Atlantic Ocean, and also a strong easterly fetch across Long Island Sound to the east of the city could bring multiple storm surges into the city!
This could very well be a worst case scenario for the Nation's most populated city. Early projections are for a surge of between 10 and 12 feet with higher waves. This could inundate much of the city!
I am reminded of the scene from the 2004 fiction, "The Day After Tomorrow", where among several other disasters, a giant tidal wave struck New York.
Now this seems to be a bit on the sensational side, however, it would be dangerous to underestimate the potential dangers associated with this storm.
One thing is for sure, this is no Irene and this is no typical category 1 hurricane.
Meteorologist Jeremy Kappell